Spiked bumper

ABSTRACT

A spiked-bumper mounted to a forward end portion of a main body of a chain saw includes a reference mounting hole formed at one longitudinal end portion of the spiked-bumper, and mounting adjusting holes formed at a longitudinal opposite end portion of the spiked-bumper in positions located on an arc constituting a part of an imaginary circle centered at the center of the reference mounting hole for adjusting the position in which the spiked-bumper is secured to the forward end portion of the main body of the chain saw.

This application is a continuation of application Ser. No. 662,499,filed Oct. 18, 1984, now abandoned.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a spiked-bumper of a portable chain sawgenerally used for felling trees and producing lumber.

2. Description of the Prior Art

Generally, a chain saw usually has a spiked-bumper mounted to a forwardend portion of a main body of the chain saw in a position close to aguide bar for guiding a saw chain in its movement around an outerperiphery of the guide bar. The spiked-bumper is caused to press againsta tree or a timber positively before a sawing operation is performed toprevent an accident from occurring inadvertently as the main body of thechain saw is pulled suddenly toward the tree or timber or the saw chainslips during operations.

Some disadvantages are associated with the spiked-bumper of the priorart. One of them is that the optimum range of application of thespiked-bumper is narrow with regard to the shape and diameter of thetrees and timbers constituting the objects of the operation, so that amultiplicity of spiked-bumpers should be provided to be fitted todifferent types of sizes of chain saw.

SUMMARY OF THE INVENTION

1. Object of the Invention

This invention has been developed for the purpose of obviating theaforesaid disadvantage of the prior art. Accordingly, the invention hasas its object the provision of a spiked-bumper of simple constructionwhich is easy to handle and which has a wide range of application withregard to the shape and diameter of the trees and timbers.

2. Statement of the Invention

According to the invention, there is provided a spiked-bumper of a chainsaw mounted to a forward end portion of a main body of the chain saw ina position close to a guide bar for guiding a saw chain in its movementaround an outer periphery of the guide bar, comprising a mountingreference hole formed at one longitudinal end portion of thespiked-bumper for securing the spiked-bumper to the forward end portionof the main body of the chain saw, and at least one mounting adjustinghole formed at an longitudinal opposite end portion of the spiked-bumperin positions located on an arc constituting a part of an imaginarycircle which is centered at the center of the mounting reference holefor adjusting the position in which the spiked-bumper is secured to theforward end portion of the main body of the chain saw.

The spiked-bumper of the aforesaid construction according to theinvention enables the position in which it is mounted to a chain saw tobe readily and positively adjusted in conformity with the shape andthickness of a tree or a timber constituting the object of a sawingoperation. Thus, the spiked-bumper according to the invention is capableof achieving maximum effects in absorbing shocks in a wide range ofapplication and can be commonly used with different types and sizes ofchain saw, so that it can improve efficiency in performing theoperations of felling trees and producing lumber by sawing timbers.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a schematic side view, with certain parts being broken away,of a chain saw having a spiked-bumper of the prior art mounted thereto;

FIG. 2 is a side view, on an enlarged scale, of the spiked-bumper of theprior art shown in FIG. 1;

FIG. 3 is a side view of the spiked-bumper comprising one embodiment ofthe invention;

FIG. 4 is a view in explanation of the manner in which the spiked-bumpershown in FIG. 3 is used; and

FIG. 5 is a side view, with certain parts being broken away, of thespiked-bumper comprising another embodiment of the invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Before describing the preferred embodiments of the invention, aconventional chain saw provided with a spiked-bumper of the prior artwill be outlined by referring to FIGS. 1 and 2, to enable the inventionto be fully understood.

The conventional chain saw comprises a main body 1 having mountedtherein an internal combustion engine which may be an air-cooledgasoline engine of a small size built in the main body 1 and serving asa power source. The chain saw further comprises a guide bar 2 projectingforwardly from a forward end portion of the main body 1, and a saw chain3 mounted on an outer periphery of the guide bar 2 for movement aroundthe outer periphery. The saw chain 3 is driven by the internalcombustion engine supported in the main body 1 to saw a tree or a timberduring operations.

A spiked-bumper 4 is mounted to the forward end portion of the main body1 by a pair of bolts 5 and 6 and located in close proximity to and inparallel with an end portion of the guide bar 2 near the operator. Thespiked-bumper 4, which is formed as of steel in the form of a flat barhaving round holes 7 and 8 for receiving the bolts 5 and 6 respectivelylocated at longitudinal opposite end portions as clearly seen in FIG. 2,is formed integrally with a plurality of teeth 9, 10, 11, 12, 13 and 14located at one side thereof and extending outwardly. Of all the teeth9-14 of the spiked-bumper 4, those teeth 12, 13 and 14 which are locatednear an end portion of the spiked-bumper 4 formed with the round hole 8are shaped such that their tips are located on a curve projectingoutwardly, and the spiked-bumper 4 is mounted to the forward end portionof the main body 1 in such a manner that the longitudinal end portionformed with the round hole 8 is secured in place by the bolt 6, as shownin FIG. 1, to a lower end portion of the forward end portion of the mainbody 1 and an opposite longitudinal end portion formed with the roundhole 7 is secured in place by the bolt 5 to an upper end portion of theforward end portion of the main body 1.

FIG. 3 shows one embodiment of the invention wherein a spiked-bumper 20formed of a material similar to that used for forming the conventionalspiked-bumper 4 shown in FIGS. 1 and 2 is formed with a mountingreference hole 21 at one longitudinal end portion thereof. The bolt 5shown in FIG. 1 is threadably engaged in the mounting reference hole 21and connected to the forward end portion of the main body 1 of the chainsaw, so that the one longitudinal end portion of the spiked-bumper 20having the mounting reference hole 21 is secured and rigidly fixed tothe upper end portion of the forward end portion of the main body 1. Ascan be seen, the hole 21 is located beyond the upper edge of the chainguide bar 2.

The spiked-bumper 20 is further formed with two mounting adjusting holes22 and 23 at an longitudinal opposite end portion thereof. The twoadjusting mounting holes 22 and 23 each have a center located on a shortarc forming a part of an imaginary circle centered at the center of themounting reference hole 21, it being seen that the length of the arc issmaller than the distance between the hole 21 and the arc. When thechain saw is used, the bolt 6 shown in FIG. 1 is passed through one ofthe mounting adjusting holes 22 and 23 to secure and rigidly fix thelongitudinal opposite end portion of the spiked-bumper 20 to the lowerend portion of the forward end portion of the main body 1 of the chainsaw, which is beyond the lower edge of the chain guide bar 2.

The spiked-bumper 20 is formed integrally with six teeth 24, 25, 26, 27,28 and 29 located at one side thereof and extending outwardly. Of allthe teeth 24-29, those teeth 27, 28 and 29 which are located near thelongitudinal opposite end portion formed with the mounting adjustingholes 22 and 23 are shaped such that their tips are located on asubstantially straight line, so that they can readily catch against atree or a timber.

Operation of the spiked-bumper 20 according to the invention will bedescribed by referring to FIG. 4. When an operation is performed to sawa tree T₁ of a relatively large diameter, the bolt 6 is inserted in themounting adjusting hole 23 and the longitudinal opposite end portion ora lower end portion of the spiked-bumper 20 is secured to the main body1 in a position close to the main body 1. By this arrangement, the chainsaw can be optimally positioned against the tree T₁ with the teeth 28and 29 pressing thereagainst. When the tree to be sawed is a tree T₂ ofa relatively small diameter, the bolt 6 is inserted in the mountingadjusting hole 22 and the spiked-bumper 20 is secured to the main body 1in a position in which the lower end portion of the spiked-bumper 20projects forwardly. When the spiked-bumper 20 is in this position, it iscapable of achieving a maximum shock absorbing effect with the teeth 28and 29 positively pressing against the tree T₂.

FIG. 5 shows another embodiment of the invention in which thespiked-bumper 30 is formed at one longitudinal end portion with amounting reference hole, not shown, and at an longitudinal opposite endportion with a mounting adjusting slot 31 in the form of an arc forminga part of an imaginary circle which is centered at the center of themounting reference hole at the one longitudinal end portion of thespiked-bumper 30. The position in which the longitudinal opposite endportion or lower end portion of the spiked-bumper 30 is secured to themain body 1 of the chain saw can be freely selected within the range ofthe length of the mounting adjusting slot 31.

What is claimed is:
 1. An elongated spiked-bumper mounted to a forwardend portion of a main body of a chain saw in a position adjacent andtransverse to a guide bar for guiding a saw chain in its movement aroundan outer periphery of the guide bar, comprising:a mounting referencehole formed at one longitudinal end portion of the spiked-bumper forsecuring the spiked-bumper to the forward end portion of the main bodyof the chain saw beyond one edge of the guide bar; and at least onemounting adjusting hole formed at a lower longitudinal opposite endportion of the spiked-bumper, positioned beyond the other edge of theguide bar, said at least one mounting adjusting hole effectivelyextending on a short arc constituting a part of an imaginary circlewhich is centered at the center of the mounting reference hole foradjusting the position in which the spiked-bumper is secured to theforward end portion of the main body of the chain saw; wherein saidspiked-bumper is rotably adjustable to move said lower longitudinalopposite end portion forward for sawing smaller trees.
 2. Aspiked-bumper as claimed in claim 1, wherein said at least one mountingadjusting hole comprises two round holes located in positions spacedapart from each other in the direction of the arc.
 3. A spiked-bumper asclaimed in claim 1, wherein said at least one mounting adjusting holecomprises a slot extending in the direction of the arc.
 4. Aspiked-bumper as claimed in claim 1, comprising at least two teethextending outwardly from one side of the spiked-bumper near thelongitudinal opposite end portion of the spiked-bumper at which said atleast one mounting adjusting hole is formed, said teeth being shapedsuch that their tips are located on a substantially straight line.
 5. Anelongated spiked-bumper mounted to a forward end portion of a main bodyof a chain saw in a position adjacent and transverse to a guide bar forguiding a saw chain in its movement around an outer periphery of theguide bar, comprising:a mounting reference hole formed at an upperlongitudinal end portion of the spiked-bumper for securing thespiked-bumper to the forward upper end portion of the main body of thechain saw; and adjusting hole means formed at a lower longitudinalopposite end portion of the spiked-bumper to provide a plurality ofrigidly fixed mounting positions located on an arc constituting a partof an imaginary circle which is centered at the center of the mountingreference hole, for adjusting and rigidly fixing the position in whichthe spiked-bumper is secured to the forward bottom end portion of themain body of the chain saw, the length of the arc along which saidbottom end portion of the spiked-bumper can move being smaller than thedistance between the mounting reference hole and the arc; said elongatedspiked-bumper having a number of teeth greater than three, and whereinthe bottom three teeth are shaped such that their tips are located on asubstantially straight line; wherein said spiked-bumper is rotablyadjustable to move said lower longitudinal opposite end portion forwardfor sawing smaller trees.